Heat-indicator for ovens



(No Model.)

E. G. NUNN.

'HEAT INDICATOR POR WENS. l No. 306,030. Patented Sept. 30, 1884.

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O v to WJTJVE j l y SSES UWM/TOR ttor-neg UNITED STATES PATENT OEEIcE.

EMMA G. NUNN, OF VASSAR, MICHIGAN.

HEAT-INDICATOR FOR OVENS.

SPECIFICATION forming part of Letters Patent No. 306,030, datedSeptember 30, 1884.

Application filed June 7, 1884. (No model.)

To aZZ whom t may concern.:

Be it known that I, EMMA G. NUNN, a citizen of the United States,residing atVassar, in the county'of rluscola and State of Michigan, haveinvented certain new and useful Improvements in Heat-Indicators forOvens, of which the following is a specification, refrence being hadtherein to the accompanying drawings.

My invention is a heat-indicator to be attached to stoves, ranges, 8vo.,to show at all times the temperature of the oven; and it consists in theparts which will be hereinafter de scribed, and pointed out in theclaims.

In the accompanying drawings, Figure lis a perspective face view of mydevice. Fig. 2 is a rear elevation of the device, and Fig. 3 is a detailside view.

Like letters indicate like parts throughout the several views. l.

A is a rod flattened at the center and ends.

The ends A are provided with openings for the reception of screws orrivets, by means of which the rod is secured in the oven of astove orrange B is a vertical rod secured at A2 to the apex of the eXpansiblerod A. The top of rod B at B rests under bar O. The rod Bmay be jointedto the bar O. Said bar is pivoted at O between the standards D D. Thestandard D is fixed to the baclrof the disk.

E is an armjointed at E to the loose end of the bar C.

F is an arm, provided on its loose end with a toothed segmental piece,I-I. The arm F is jointed at F to the arm E.

G is a vertical standard fixed to the supporting-frame I. Said frame isprovided with an opening, I, to admit the vertical rod B. The arm F ispivoted at G to the top of standard G'.

K is a toothed wheel fixed to the dial-shaft between the standards D D.

L represents the dial, and M the hand or indicator thereon. N is a zerostop on the face of the dial. Said dial-face is provided with a seriesof numbers representing degrees of heat. J is a bracket fixed to thestove in front of the pipe, on which the frame I, dial,

- &c., aremounted. If a stove has an elevated oven, the dial should beplaced in the front of said oven.

The operation of the device is as follows: The ends A of the expansiblerod A are rigidly iixed in the oven, and the rod B and Vinterveningmechanism so adjusted that when there is no heat in the oven the handwill point to zero on the dial. When in that condition, the parts willbe in the position substantially as shown in Fig. 2 of the drawings.

When the oven is heated, the rod A, being subjected to the heat,necessarily expands. The

ends of said rod being rigidly secured, the expansion will manifestitself by lifting apex at A2. Such expansion will lift the rod B, bar O,and the arms E and F, by means of their jointed and pivoted arrangement,as hereinbefore speciiied. The segmental teeth of the piece H engagesthe spur-wheel K. Therefore by lifting the arm F the segmental piece israised and the spur-wheel and dialshaft K rotated, and the hand M movedon the face of the dial. By this means the heat inan oven may beaccurately and at all times indicated bythe hand and figures on thedialplate. As the oven is cooled the expansible Vrod A contracts,thereby turning the hand back on the dial.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. In a heat-indicator, the expansiblc rod A,vertical rod B, resting under bar O or jointed thereto, arms E and F,and segmental tootlrpiece H, the arm F being pivoted to the standard G,in combination with the spurwheel K, hand M, and shaft K', said shaftbeing mounted in the standards D D, substantially as described, and forthe purposes set forth.

2. In a heat-indicator, the expansible rod A, and vertical rod B,pivoted bar O, arms E and F, and the standards G and D D', saidstandards being mounted on the frame I, in combination with the shaftK', spur-wheel K, hand M, and dial L, substantially as described, andfor the purposes set forth.

3. In a heatind1cator, a bent expansible rod having its ends secured inan oven, said rod being provided with a vertical rod, in combinationwith a dial and hand, and mechanism intervening between said hand andver-4 tical rod whereby the temperature of an oven may be determined,substantially as described, and for the purposes set forth.

In testimony whereof I afx my signature in presence of two witnesses.

EMMA G. NUNN.

W'itnesses:

C. C. GUETrs, H. E. PRATT.

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